描述电路的基本组成部分

Do the children recognise that battery powered devices use electricity?  
Are the children using the correct names for the components?  
Can they make a complete circuit to power a bulb?  
Can they describe the flow of electricity round the circuit through the component and back to the battery or power source again?  
Can they explain how the LED lights?

Quizzes available in pupil zone.

Unit knowledge organiser and test available in unit / lesson documents area.

The Science Behind the Science
Circuits need power sources such as batteries. Wires are connected to both the positive and negative ends of the battery (or cell). Circuits contain other electrical components such as bulbs and motors, which allow the electricity to pass through them. Electricity will only flow and travel around a circuit that is complete. They cannot have any gaps or else the electricity cannot pass through and there must be no short circuits. 

The basic parts of a circuit include: the battery, the wire(s), the bulb(s), buzzer(s), motor(s) and switches (on and off). When the switch is open, there is a gap in the circuit. This means that the switch is off, and that electricity cannot pass around the circuit. When the switch is closed, the electricity can travel around the circuit as the switch is on. If you add more batteries to a circuit, this will increase the power source (electrical energy) and will make the bulb a lot brighter. The more bulbs you add to a simple circuit, the less the electrical energy, which will make the bulbs a lot dimmer. 

If you have longer wires, the electrical energy has a lot longer to travel around the circuit. This will also make the bulb a lot dimmer. Motors rotate when electrical energy is flowing around the circuit. Common electrical appliances include: refrigerators, freezers, washing machines, dishwashers, microwaves, ovens, hairdryers, toasters, vacuum cleaners etc. 

Mission Assignment: Today we are looking at fruit-powered batteries. The acid comes from the citric acid inside of the lemon. The two metal components are zinc and copper and they are electrodes. Electrodes are the component in the circuit where the electric current enters and leaves the battery. With the zinc and copper set-up, the current will flow out of the penny and into the nail. This can be seen in the video. Once the fruit-power battery is connected to the LED, a complete circuit is made. As the electric current passes through this LED, it lights up the LED and passes back through all the lemons. 

There are various types of citrus fruits. You could also try this out with limes and oranges etc. The more acidic the fruit is, the better it is for conducting electricity. This explains why the fruit battery works even when the copper nails are not touching each other. The citric fruit contains positively charged ions. When the nail is inserted into the fruit, the negatively charged ions start to move from the fruit into the zinc nail. This leaves the protons in the fruit. It is the transfer of electrons that generates electricity as soon as the wire is attached to the nail and the bulb lights up.